1. Field of the Invention
The present invention relates to a label having transparent and opaque label areas.
2. The Prior Art
Labels of this type are used, among other times, when the fill level of a labeled transparent container is to be registered from different angles at a glance, or if other objects located below and/or behind the label, such as displays, are to be visible through the label.
The opaque and transparent areas in a label are typically implemented by providing a transparent label film with opaque, usually white background printing, with only the area of the window being left out and therefore remaining transparent. Printing over almost the entire area has the disadvantages that it is not only relatively expensive because of the high consumption of printing ink, but also that the multiple screen printing procedures which are usually necessary make the manufacturing process very complex. Leaving the label film entirely transparent usually does not represent an alternative, since a text imprint would only be readable with difficulty or practically not at all—particularly with labels that overlap themselves, having printing in the overlapped and overlapping areas. Transparent areas are typically unavoidable precisely in container labels which overlap themselves when stuck on as intended, in order to be able to check the container fill level. The dimensions of corresponding labels in the dispensing direction may be from somewhat more than one time to multiple times the container circumference. Labels of this type are frequently referred to as “overwrapping” labels.
Overwrapping labels are used above all for identifying pharmaceutical containers, such as infusion bottles, injection ampoules, tablet bottles, medication bottles, etc., since a small container size is often faced by a large amount of information which is to be attached to the container. Thus, often nearly the entire container surface is needed for typical tasks such as active ingredient identification and dosing, package size, usage instructions, batch number, and expiration date, sometimes in more than one language. If necessary, the lateral surface of a container may be used multiple times by applying overwrapping labels. For this purpose, arrangements are made which allow and/or simplify at least partial unwinding of the label from the container, so that the information which is printed on the label areas covered by the overlap is accessible. These arrangements may include grip tabs on the label edge (which trails during dispensing), which have no pressure-sensitive adhesive coating or one having reduced adhesive force on their bottom side, as well as adhesion-reducing coatings, such as a silicone treatment.
Like other labels in the medical/pharmaceutical field, overwrapping labels are often implemented so that parts of the label may be separated from the rest of the label using perforation lines or separating layers, for example. The separated areas, which are often referred to as voucher sections, may be archived separately, for example, stuck in patient files or laboratory notebooks, in order to log the administration of a specific dose of a specific active ingredient. The voucher sections are usually areas of the overlapping label part. Correspondingly implemented overwrapping labels are described in European Patent No. EP 0 463 193 A1, among others.
In the meantime, overwrapping labels having suspension tabs for infusion bottles to be hung upside down have also appeared on the market. The bow-shaped suspension tabs, which may be pulled out of the film plane of the remaining label glued onto the container, are intended to be hung on the hook of an infusion stand or the like. In labels having suspension tabs, the overwrapping arrangement offers the advantage that the adhesive bond between the container to be suspended and the label is only subjected to thrust loads, but no peeling loads, since the label is glued to itself due to the self-overlapping arrangement. This advantage particularly comes to bear if the container to be suspended is a glass container, since the adhesive bond “plastic on plastic” between the overlapping label areas is more stable than an adhesive bond “plastic on glass”. This is even more true if the container surface is slightly contaminated and if the labeled container is tempered in a water bath. Typical contaminants are oil residues, water drops, hand sweat and/or oil, cleaners, and other chemicals. The adhesive force of an adhesive bond on glass is worsened by a water bath treatment, since hydrogen bridge bonds between the silicates of the glass and the carbonyl groups of the adhesive bond break. Tempering in a water bath is common in medical use, and thus labels having suspension tabs must withstand a water bath test in order to ensure functional reliability in use according to DIN 58 376.
The overwrapping labels having a suspension tab on the market are opaque and therefore have the disadvantage that it is hardly possible to observe the fill level. For this reason, a majority of typical labels having suspension tabs are not implemented as self-overlapping and are equipped with especially stable, but also costly, adhesives for this purpose. High failure safety of overwrapping labels is usually not entirely achieved, however. In principle, labels having suspension tabs are known, for example, from German Patent Nos. DE 39 07 862 A1 and DE 91 01 464 U1, as well as European Patent Nos. EP 0 356 574 A2 and EP 0 632 422 A1.